The present invention relates to a plasma-resistant member for a semiconductor manufacturing apparatus, such as a plasma vessel, a dome, a bell jar, a window material, or a dielectric plate in an apparatus for performing treatment with halide plasma of fluorine, chlorine or the like, for use in CVD, etching treatment, or the like, and a method for manufacturing the plasma-resistant member.
In the related art, as plasma-resistant members for a semiconductor manufacturing apparatus, plasma-resistant members made of high-purity alumina ceramics formed by sintering or firing, in the atmosphere, molded pieces obtained out of alumina (Al2O3) powder with a purity of at least 99.5% have been generally used. Further, when metal contamination becomes an issue, plasma-resistant members made of super-high-purity alumina ceramics formed by sintering or firing, in the atmosphere, molded pieces obtained out of alumina powder with a purity of at least 99.9% have been used.
On the other hand, in recent years, there are also known plasma-resistant members made of yttrium oxide (Y2O3) or yttrium aluminum garnet (YAG: Y3Al5O12) ceramics having superior resistance against halide plasma to alumina ceramics.
However, according to the current 0.1 μm semiconductor design rule, metal contamination such as Fe (iron) or the like is generated in the conventional plasma-resistant members for a semiconductor manufacturing apparatus. Thus, there occurs disadvantageously a failure of semiconductor devices.
Incidentally, a desired level of Fe contamination in a semiconductor wafer is not higher than 1×10E10 (1×1010) atoms/cm2 in the case of poly-Si etcher. It is considered that the reason why such a disadvantage occurs is that about 3-20 ppm metal impurities of Fe and so on have been already contained on the raw material level even in super-high-purity alumina powder having a purity of 99.99% industrially available at present.
Thus, in a surface layer of a plasma-resistant member made of high-purity alumina ceramics formed by sintering or firing, in the atmosphere, a molded piece obtained out of usual powder with a purity of at least 99.5%, Fe and so on contained in the raw material are contained as they are.
On the other hand, also in the case of a plasma-resistant member made of yttrium oxide and/or yttrium aluminum garnet ceramics, metal impurities have been already contained on the raw material level. Thus, contamination is caused on a semiconductor wafer in the same manner.